1. Field of the Invention
The present invention relates to improvements in monitoring and controlling substation power distribution. Specifically, the invention involves a method and apparatus for automatically monitoring substation power distribution and usage and transmitting the information to a remote location in order to provide real time, improved-accuracy monitoring of consumer loads and to control a power distribution substation from a remote location.
2. Description of the Related Art
At each power substation, there are generally transmission and distribution circuits, transformers, circuit breakers, capacitor banks, and other electrical equipment (hereinafter "power equipment") which deliver electrical power. The various pieces of electrical equipment, including the circuits and transformers, are protected for overload and fault conditions by monitoring the current in each phase of the equipment. The normal method of monitoring this current is by using a current transformer. A current transformer transforms the primary current (normally in the range of 100 to 3000 amps) to a secondary current in the range of 5 amps. The secondary current is then monitored via protection equipment, and upon detection of an overload or fault, the protection equipment will trip (open) the appropriate breakers to terminate the fault.
Because the current transformer has a known primary to secondary ratio, the current transformer can also be considered as a current sensor. This current sensor is used via a transducer in many substations to provide a DC signal which is representative of the primary current.